Pillarless Duplexer Antenna Structure for Parasitic Coupling Isolation
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Solution Overview
Problem
Existing duplexer designs suffer from parasitic signal coupling between transmit and receive terminals due to conductive paths through the side wall and cap wafer, which can saturate receive circuitry and interfere with reception.
Innovation Solution
The duplexer design eliminates conductive residues and introduces a trap-rich layer in the cap wafer to reduce parasitic coupling by removing adhesion and oxide layers between the antenna terminal and side wall, and omits the post connecting the antenna terminal to the cap wafer, enhancing mechanical stability with additional metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a post is disposed on the antenna terminal and in contact with the cap wafer to provide mechanical support, then mechanical stability is improved, but parasitic signal coupling between transmit and receive terminals increases due to conductive paths through the side wall and cap wafer
Solution Approach 1:
The patent removes the conductive post that connected the antenna terminal to the cap wafer, extracting the harmful conductive path while maintaining mechanical stability through alternative means. The post is completely eliminated from the antenna terminal structure, severing the parasitic coupling path to the cap wafer and side wall.
Solution Approach 2:
The patent introduces a non-conductive intermediary layer (adhesion layer) between the antenna terminal and the cap wafer. This layer acts as a mediator that provides mechanical support and bonding while blocking the conductive path, thereby maintaining structural integrity while preventing parasitic signal coupling.
2Reliability
If adhesion and oxide layers are present between the antenna terminal and side wall to ensure proper bonding, then manufacturing reliability is improved, but parasitic coupling increases due to conductive residues
Solution Approach 1:
The patent selectively removes the adhesion and oxide layers from the regions where they would create conductive paths to the side wall, while maintaining layers in areas needed for structural bonding. This extraction eliminates conductive residues that cause parasitic coupling while preserving manufacturing reliability in critical bonding zones.
Solution Approach 2:
The patent applies different layer configurations to different regions: adhesion and oxide layers are removed in areas adjacent to the side wall where they would create parasitic paths, but may be retained in other areas where bonding is required. This local differentiation optimizes both electrical performance and mechanical reliability.
3Stability of the object's composition
If a conventional duplexer design with posts and conductive layers is used to ensure mechanical stability, then structural integrity is improved, but signal isolation between transmit and receive terminals deteriorates
Solution Approach 1:
The patent extracts the conductive post structure that created parasitic coupling paths, removing the source of interference while maintaining structural integrity through alternative non-conductive support mechanisms. The cap wafer and side wall structure is retained but decoupled from the antenna terminal.
Solution Approach 2:
The patent introduces non-conductive intermediary structures between the antenna terminal and the cap wafer/side wall assembly, using adhesion layers and spatial gaps as mediators that maintain mechanical stability while blocking electrical coupling paths, thereby achieving both structural integrity and signal isolation.
Data Source
AI summary
A duplexer including a support substrate, a reception signal terminal, a transmit signal terminal, an antenna terminal, a receive side filter formed on the support substrate and electrically coupling the reception signal terminal to the antenna terminal, a transmit side filter formed on the support substrate and electrically coupling the transmit signal terminal to the antenna terminal, a side wall surrounding the receive side filter and the transmit side filter, and a cap wafer disposed on the side wall and enclosing the receive side filter and the transmit side filter in a cavity defined by the cap wafer, the side wall, and the support substrate, there being no post disposed on the antenna terminal and in contact with the cap wafer.